Adjustable eccentric for sewing machines



June 6, 1939. R. KAIER V ADJUSTABLE ECCENTRIC FOR SEWING MACHINES Filed April 23, 1938v 2 Sheets-Sheet 1 L'e/Lrd [fallar June 6, 'l939. R. KAIER ADJUSTABLE ECCENTRIC FOR SEWING MACHINES Filed April 23 1938 2 Sheets-Sheet 2 Patented June 6, 1939 PATENT OFFICE `ADJUSTABLE ECCENTRIC FOR SEWING MACHINES Richard Kaier, Cranford, N. Jl., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application April 23,

7 Claims.

'I'his invention relates to an eccentric for use with a sewing machine and more particularly to a feed actuating eccentric which may be adjusted to vary its eccentricity.

'Ihe primary object of this invention is to provide an improved high speed actuating eccentric which is readily adjustable and which is positively locked in its adjusted position.

With the above and more specific objects in 10 view. the invention comprises the devices, combinations, and arrangements of parts hereinafter described in connection with the accompanying drawings from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the In the drawings:- Fig. 1 is a vertical section taken through the center of a machine having my invention embodied therein.

Fig. 18L is a fragmentary view showing the stitch length indicator.

Fig. 2 is a vertical section taken substantially along the line 2--2 of Fig. 1.

the feeding eccentrica Figs. 4 and 5 are sectional views taken along the. lines 4-4 and 5-5 of Fig. 3.

Fig. 6 is a disassembled perspective view of the adjustable eccentric.

Referring to the drawings the present improvements have been embodied in a sewing machineincluding a frame comprisinga bed III, from one end of which rises the hollow standard II of a terminating at its free end in 'a hollow head I3. Journalled in the bracket arm I2 for rotary movement is a needle-bar f actuating shaft, I4. having a balance wheel I5 fixed to one of its endswith. Carried by and rotatable relative tothe shaft I4 isan adjusting eccentric 24 whichvex- 50 tends into the centrally located aperturev 25 in the feed advancing eccentric 23.- The aperture 25 in the eccentric 23 is velongated transverse of the direction of movement of the plate 22 so that the eccentric 24 has aline contact with-the .55 inner surface of the eccentricV 23 in the direc- Flg. 3 is an enlarged sectional view through tubular bracket arm,l2 overhangingl the bed and 1938, Serial No. 203,728

tion of movement of the plate and at points diametrically opposite each other. Made integral with the adjusting eccentric 24 is a disk 26 formed with a slideway 21 which receives a slidable locking plate 2B formed with teeth 29 which are adapted to engage the teeth on a ilange 32 formed on a feed lift eccentric 33 which is fixed to the shaft I4 by means of a set screw 34. 'I'he disk 2l is provided with a stud 35 which carries a spring 3B, one of the ends of which reacts against the shoulder 31 of the locking plate 28 and the other end reacts against the periphery of the disk 25. 'I'he spring 36 urges the plate-23 so that the teeth 29 on the plate vand the teeth 30 on the `flange 32 are-normally engaged. In order to more effectively lock the disk 26and eccentric 24 to the flange 32 when the machine is operating at high speed, the end 3l of the plate 23, which is on the opposite side of the shaft I4 from the teeth 29, is made heavier than the end carrying the teeth so that centrifugal force will assist in lholding the teeth 29 and 3 3 in engagement.

The feed lift leccentric; 33 actuates a pitman 4I! whichis connected ,to an arm 4I on the'rock shaft `42 Fig. 2. The.feed advancing eccentric 23 actuates 'a pitman43 which Ais connected to an arm 44 on therock shaft.45. A feed dog 45 which cooperates with a presser-foot 41 to ad- Vance the material is carried bythe feed bar 43, which has one of .its ends` pivotally connected to the upstand-ing arms49 on the. rock shaft 45 and its otherv end operatively connected to the arm 50 on the rock' shaft'42t From the above it will be obvious: that eccentric 33 will impart to the feed :dog 45 a rising and vfalling movement land thej eccentric 23 will impart a feed and return movement". f f

In order that the" operator may vary the 4amount vof V feeclingr-movement imparted to the feed dog, a plunger 52 extends through an open.

ing inthe wallof the standard II and is spring urged. outwardlybymeans of a spring 53 which extends through a hole in the plunger 52 and is secured to the .wall4 of the standard by the screw 54. `To prevent unauthorized adjustment of the f eccentric the' screw 54 and spring 53 may be removed,` andthe plunger 52`.withdrawn from the openingr The screw52 may then be inserted to 2l, Fig. Brand slides it against the action of the spring 38 so that the vteeth 20 are disengaged from the teeth thereby unlocking the disk 20 from the flange 32. 'Ihe disk 2B and adjusting cam 24 are held stationary by the end l1 of the plunger 52 and when the shaft Il is turned the movement of the eccentric 24 relative to the shaft Il shifts the plate `22 and eccentric 23 in a right line and relative to the shaft I4 to vary the amount of movement imparted to the pitman 43 and feed dog 40.

To indicate the number of stitches per inch to which the feeding mechanism has been adjusted, a pointer 58 (Fig. 1) is fixed to the standard Il and a semi-circular plate 58, having suitable indicia thereon, is fixed to the balance wheel l5.

The eccentric 33 is formed with a gear portion 60 having teeth which mesh with'a gear 8l on a .vertical shaft 62. Also fixed to the shaft 82 is a second gear 63 which meshes with a gear 84 car-I` ried by the hook shaft 65 journalledin suitable bearings on the bed I0. The gear ratio between the needle-bar shaft i4 and the hook shaft 85 is as 1:2 and, therefore the shaft' 85 makes two complete rotations for each rotation of the needlemachine, reference may be had to my co-pending Vbar shaft I4.

Fixed to the shaft BI is a hook 86 which cooperates with a needle I9 in the formation of stitches. For a more complete understanding of the stitch-forming mechanism of the application Serial No. 152,707, filed July 9, 1937.

From the foregoing it will be observed that the higher the speed of the machine the greater the centrifugal force of the weighted end 38 of the locking plate 28 and as the weighted end 38 is diametrically opposite the teeth 29, it is obvious that these teeth will be pulled into contact with the teeth 30 with a greater force when the machine is operating at high speed than when it is operating at a slow speed.

Having thus set forth the nature of the invention what I claim herein is:-

1. In a sewing machine, a rotary shaft, a collar formed with a groove and secured to said shaft,

- a feed advance eccentric rotatable with said collar and slidable in said groove, said eccentric being formed with a centrally located opening, an adjustable eccentric rotatable relative to said shaft and extending into the opening in said feed advance eccentric, means for rotating said adjusting eccentric relative to said shaft, and spring biased means for locking said adjusting eccentric to said shaft.

2. In a sewing machine, a rotary shaft, a collar formed with a groove and secured to said shaft, a

feed advance eccentric rotatable with said collar and slidable inv said groove, .said eccentric being formed with a centrally located opening, an adjustable eccentricrrotatable relative to said shaft and extending into the opening in said feed advance eccentric, means for rotating said adjusting eccentric relative to said shaft, and a slide plate carried by said adjusting eccentric and having means thereon for locking said adjusting eccentric.

3. In a sewing machine, a rotary shaft, a collar formed with a groove and secured to said shaft, a feed advance eccentric rotatable with said collar and slidable in said groove, said eccentric being formed with a centrally located opening, an adjustable eccentric rotatable relative to said shaft and extending into the opening in said feed t 4. In a sewing machine, a shaft, a collar fixedto said shaft and formed with a groove, an actuating eccentric slidable in the groove in said collar and formed with a centrally located opening, an eccentric extending into said opening. a disk carried by said eccentric, a spring biased locking plate slidable on said disk and having teeth thereon, and a flange fixed to said shaft and having means thereon which cooperates with the teeth on said locking plate to prevent said disk from turning when said locking plate is in normal-position.

5. In a sewing machine, a shaft, a collar fixed to said shaft and formed with a groove, an actuating eccentric slidable in the groove in said collar and formedwith a centrally located opening', an eccentric extending into said opening, a disk carried by said eccentric, a spring biased locking plate slidable on said disk and having teeth thereon, a flange fixed to said shaft and having means thereon which cooperates with the teeth on said locking plate to prevent said disk from turning when said locking plate is in normal position, and

manually controlled means for shifting said locking plate to permit said disk to be turned relative to lthe shaft.

6. In a sewing machine, a rotary shaft, an actuating eccentric carried by said shaft and shifts.- ble in a direction at right angles to the longitudinal axis of the shaft, a member for shifting said eccentric, and a plate carried by said member and having portions which are located on opposite sides of said shaft, one of said portions being provided Wtih locking means and the other portion being weighted whereby centrifugal-force will act to more effectively hold said plate in its normal position when the shaft is rotating at speed.

7. In a sewing machine, a rotary shaft, a collar fixed to said shaft, an actuating eccentric shiftable relative to said collar, an adjusting member for shifting said eccentric, a iiange on said shaft, a slidable plate carried by-Y said adjusting member and having locking means on one end thereof which engages said flange, the other end of said plate being weighted whereby centrifugal force will act to more effectively hold the locking means on said plate in engagement with said fiange when the shaft is rotated at speed.

RICHARD KAIER. 

